Download or read book Modelling of Ignition of Liquid Hydrocarbon Droplets at High Pressure microform written by Renata Ruszalo and published by National Library of Canada = Bibliothèque nationale du Canada. This book was released on 1991 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Modelling of Ignition of Liquid Hydrocarbon Droplets at High Pressure written by Renata Ruszalo and published by . This book was released on 1991 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Droplets and Sprays written by Saptarshi Basu and published by Springer. This book was released on 2017-12-11 with total page 433 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on droplets and sprays relevant to combustion and propulsion applications. The book includes fundamental studies on the heating, evaporation and combustion of individual droplets and basic mechanisms of spray formation. The contents also extend to the latest analytical, numerical and experimental techniques for investigating the behavior of sprays in devices like combustion engines and gas turbines. In addition, the book explores several emerging areas like interactions between sprays and flames and the dynamic characteristics of spray combustion systems on the fundamental side, as well as the development of novel fuel injectors for specific devices on the application side. Given its breadth of coverage, the book will benefit researchers and professionals alike.

Download or read book Study of the Sub and Supercritical Behavior of Fuel Droplets written by and published by . This book was released on 2001 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A study of the droplet gasification and combustion characteristics of hydrocarbon fuel droplets was conducted at sub- and supercritical. The experimental setup provided quiescent and convective environments under supercritical pressure and temperature conditions. The droplet combustion experiment hardware consisted of: a liquid pressurizing and transfer system; a high pressure and temperature combustion chamber; a droplet formation, deployment and ignition system; and a high speed CCD imaging system. The gasification and combustion characteristics of droplets of several hydrocarbons under quiescent environments were studied. Specifically, the mass emission rates and combustion characteristics of 1.5-mm-diameter suspended droplets of a series of hydrocarbons ranging from hexane (C6) to tetradecane (Cl4) were measured at sub- and supercritical pressures and temperatures using the high-speed image system. The images of droplet gasification and combustion revealed interesting phenomena and provided better understanding of the droplet behavior in sub- and supercritical pressure and temperature environments.

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 568 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Analysis of Droplet Combustion A Theoretical Approach written by Shah Shahood Alam and published by LAP Lambert Academic Publishing. This book was released on 2015-03-23 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt: The findings of this work provides an insight into the fundamental aspects of liquid droplet combustion modelling by developing different droplet sub models. An unsteady, spherically symmetric, sub critical, single component gas phase model is developed first and tested for various ambient conditions of temperature, pressure, composition and fuels.It is further extended to include the effects of convection, droplet heating and emissions.A high pressure droplet vaporization model is evolved in view of the supercritical vaporization occuring in diesel engines and liquid rockets.Also, simple and detailed multi component droplet vaporization/combustion models are developed, since commercial fuels used in engines are multi component fuels.The discrete droplet sub models are simple and realistic requiring less computation time and therefore feasible for their implementation in spray combustion codes where CPU economy is vital.

Download or read book Evaporation and Self ignition of Multi component Hydrocarbon Fuel Oil Droplets written by Michel Isaac Michael and published by . This book was released on 1964 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Model for the Ignition and Extinction of Liquid Fuel Droplets written by M.Z. Pindera and published by . This book was released on 1979 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Burning of Hydrocarbon Fuel Droplets at High Pressures written by T. A. Ledwell and published by . This book was released on 1968 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Auto ignition of Liquid Droplets of Single and Two Component Fuels Under Pressure written by Titus S. Chen and published by . This book was released on 1995 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experimental measurements and model predictions of ignition delay times for single component and two-component liquid fuels are presented. The methodology used is the suspended-droplet/moving-furnace technique, in which a droplet of fuel is suspended from the tip of a thin quartz fibre. A preheated electric furnace moves towards and encompasses the droplet locality, producing a sudden rise in ambient temperature, and thus initiating the ignition process. The entire apparatus is enclosed in a pressure vessel and is remotely operated. Data were collected for pressures up to 18 atm absolute and in a temperature range of 773 K to 973 K. Fuels tested comprised n-paraffins (decane, dodecane, and hexadecane), aromatics (mesitylene, o-xylene, and isobutylbenzene) and a cycloparaffin (decalin), as well as selected binary combinations: n-decane/n-dodecane, n-dodecane/n-hexadecane, n-decane/decalin, n-decane/isobutylbenzene, n-decane/mesitylene, and n-decane/o-xylene. Paraffin measurements at low pressures and high temperature revealed a monotonic decrease in ignition times with increasing pressure. However, higher pressure ignitions at lower temperatures showed more complex behaviour by the measurement of two or "twinned" ignition times for the same pressure and temperature condition, indicating a change in reaction mechanism, possibly from one-stage to two-stage ignition. Aromatic fuels did not show "twinned" ignition time behaviour and responded with a slight increase in ignition times with increasing pressure, owing to a weaker reaction rate dependence on pressure. The cycloparaffin behaved analogously to the n-paraffin family. The behaviour of mixtures was largely controlled by the more volatile component. (Abstract shortened by UMI.).

Download or read book The Vaporization and Ignition of Liquid Fuel Drops written by Mohamed Ibrahim Abdou and published by . This book was released on 1959 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Introduction to Modeling and Control of Internal Combustion Engine Systems written by Lino Guzzella and published by Springer Science & Business Media. This book was released on 2013-03-14 with total page 303 pages. Available in PDF, EPUB and Kindle. Book excerpt: Internal combustion engines still have a potential for substantial improvements, particularly with regard to fuel efficiency and environmental compatibility. These goals can be achieved with help of control systems. Modeling and Control of Internal Combustion Engines (ICE) addresses these issues by offering an introduction to cost-effective model-based control system design for ICE. The primary emphasis is put on the ICE and its auxiliary devices. Mathematical models for these processes are developed in the text and selected feedforward and feedback control problems are discussed. The appendix contains a summary of the most important controller analysis and design methods, and a case study that analyzes a simplified idle-speed control problem. The book is written for students interested in the design of classical and novel ICE control systems.

Download or read book Numerical Simulation of Combustion of Single Component and Multicomponent Unsupported and Fiber supported Droplets in Micro gravity written by Narugopal Ghata and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A detailed computational study of evaporation and combustion phenomena of unsupported and fiber-supported single and multi-component droplets is presented. The current study consists of a total of five parts: (a) study the effects of support fibers on the vaporization of single component n-heptane droplets, (b) study the effects of the Marangoni stress in single component n-heptane droplet combustion, (c) study the effects of support fibers in single component n-heptane droplet combustion, (d) study soot shell formation for single component n-heptane droplet, and (e) study multi-component n-heptane/n-hexadecane droplet evaporation and combustion. The volume-of-fluid (VOF) method is employed in the studies to capture the liquid-gas interface for transient two-phase multidimensional flows. The calculations also include variable thermo-physical properties of the liquid and gas phases as well as Marangoni stresses. In the first part of the study, a detailed numerical investigation of the effects of support fibers on the vaporization of a fiber-supported n-heptane droplet in reduced gravity is presented. This part of the study also investigated the effects of the thickness of fiber, ambient pressure, and ambient temperature on droplet evaporation. The computational results were validated with experimental results. In the second part of the droplet combustion study, a detailed numerical investigation of the Marangoni effects for fiber supported n-heptane droplet combustion in reduced gravity is presented. A 21-step n-heptane reaction mechanism proposed by Machrafi et al. (2009) is incorporated to model the combustion with both low and high temperature chemistry. Predicted burning rates and flame diameters have been validated with data from drop tower experiments. The present computational results agree well with the experimental results. The primary focus in the third part of the study is on the effects of support fibers on the droplet burning rates and flame structure. A 21-step n-heptane reaction mechanism consisting of 20 species proposed by Zhang et al. (2013) is employed to model the combustion chemistry. Computed burning rates and flame stand-off ratios are compared with the experimental results of Jackson and Avedisian (1993). Predicted flame structures are also validated with the experimental results of Mikami et al. (1994). The present computational results agree well with the experimental results. The results indicate that the support fibers can have significant impact on droplet burning rates and flame structures. In the fourth part of the study, a detailed numerical investigation of unsupported and fiber supported n-heptane droplet combustion in reduced gravity is done to explore some important information i.e., the location of pyrolysis and soot shell using a complex multidimensional computational fluid dynamic (CFD) analysis with a detailed reaction mechanism. A 25-step n-heptane mechanism consisting of 21 species is incorporated to model the combustion. The reaction mechanism is validated for the ignition delay time. Computed burning rates and flame stand-off ratios for both unsupported and fiber-supported droplets have been validated with prior computational and experimental studies. The computed soot shell stand-off ratios are validated by comparisons with experimental and computational results. The present computational results agree well with the experimental results.In the fifth and final part, a numerical study of vaporization and combustion of unsupported and fiber-supported multi-component n-heptane/n-hexadecane droplet is presented.

Download or read book Droplet Combustion at High Pressures with Unsteady Effects written by Carlos Sanchez Tarifa and published by . This book was released on 1972 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt: To describe subcritical combustion, there are quasisteady theories based on the fact that the ratio of gas density to liquid density, epsilon, is small. At large pressures below critical, epsilon is not too small and unsteady effects become more important. It is found that, far from the droplet, at distances of the order of the droplet radius divided by the square root of epsilon, there is a unsteady region that originates corrections to mass burning rates, given by quasisteady theories, of order square root of epsilon. For most hydrocarbons burning in air the flame is located far from the droplet, and its position is not given, even in first approximation, by quasisteady theories. Unsteady effects are also analyzed for forced convection burning with Peclet numbers of order square root of epsilon. (Author Modified Abstract).

Download or read book Combustion Dynamics of Liquid Droplets and Turbulent Jets Relevant to Rocket Engines written by Miguel Angel Plascencia Quiroz and published by . This book was released on 2021 with total page 225 pages. Available in PDF, EPUB and Kindle. Book excerpt: These experiments examined the reactive processes involving nanoparicle laden liquid droplets, and turbulent jet flames as two separate sets of studies. The first part of this dissertation (Chapters 2 and 3) deals with the combustion of ethanol liquid droplets loaded with nano particulate additives using different droplet formation methods. For this study, an apparatus at the Energy and Propulsion Research Laboratory at UCLA was used to keep the droplet in a quiescent environment. Three different types of droplet combustion experiments were performed, involving: (I) the classic single droplet suspended from a quartz fiber, (II) a single droplet suspended from a quartz capillary, (III) a burning droplet that has continual fuel deliver to sustain the droplet for longer periods of time during the combustion process. Two alternative nanoparticles were explored to demonstrate the effect of energetic additives: reactive nano aluminum (nAl) and inert nano silicon dioxide (nSiO2), each having nominal average diameters of 80 nm. Simultaneous high speed visible and OH* chemiluminescence images were taken to determine the shape of the droplet over time and hence the burning rate constant (K), flame standoff distance, and mean OH* chemiluminescence intensity with varying particulate concentrations. Visible imaging showed particle/vapor ejections and jetting in continuously fed droplet experiments, while rod-suspended burning droplets showed limited particle ejection, usually towards the end of the droplet lifetime. The nSiO2-laden, rod-suspended droplets formed a porous, shell-like structure resembling the shape of a droplet at higher nSiO2 concentrations, in contrast to smaller residue structures left for nAl-laden droplets. A systematic increase in the burning rate constant was observed as the loading concentration of nAl was increased from 1wt%-6wt%. The droplet with continual fuel delivery had the greatest improvement in K of 13% over the pure fuel value. For nSiO2, the continuously fed droplet showed the greatest increase of 5% at 1 wt% loading concentrations, and no consistent trend was observed for nSiO2, likely due to the large shell-like residue structures in the latter stages of combustion. Transmission electron microscopy (TEM) images of particle residue revealed additional insights.The second part of this dissertation (Chapters 4 and 5) studied reacting gaseous turbulent jets in a newly constructed experiment at the Air Force Research Laboratory (AFRL/RQR) located at Edwards Air Force base. This experimental study aimed to characterize the coupling of an acoustic field with a turbulent gaseous methane nonpremixed flame under atmospheric pressure conditions. Two separate injection configurations were examined: one that involved a classic single methane jet surrounded by a minimal velocity oxidizer co-flow and a second coaxial jet configuration with annular oxidizer flow and the same low-velocity co-flow. The different jets were placed within an acoustic waveguide in which standing waves could be created using several speakers. The reacting jets could thus be situated at either a pressure node or a pressure anti-node location. High-speed Schlieren and OH* chemiluminescence images recorded the near field behavior of the flame under both unforced and acoustically forced conditions. High-speed imaging showed two different phenomena associated with these standing waves. When the flame was forced while situated at a pressure node, a sinuous oscillatory response of the flame was observed, in addition to transverse oscillations of the center fuel jet, which shortened the intact fuel core length. The flame "flattened" into an ellipsoidal shape in the direction of the acoustic waves. Conversely, at a pressure anti-node, the coupling of the acoustics and flame gave rise to an axisymmetric response (puff-like oscillations), which prompted the flame to become unstable at the anchoring region. This could lead to periodic liftoff or permanent flame liftoff. A receptivity study for a methane jet at Reynolds number of 5,300 and an ambient oxygen concentration of 40\% showed that the reacting jet was able to respond at the frequency of the unsteady acoustic field for a range of frequencies, but with a diminishing response of the flame for both the pressure node and the pressure anti-node under high frequency excitation. Proper Orthogonal Decomposition (POD) analysis was able to extract mode shapes and frequencies based on pixel intensity fluctuations. For the cases of pressure node forcing, this analysis method illustrated the different modes of flame oscillation, in many cases which were similar to corresponding low Reynolds number fuel jet experiments with pressure node excitation conducted at UCLA. A forcing susceptibility diagram was created to map the three different anchoring stability regimes the flame experienced under pressure anti-node forcing, demonstrating the need for higher amplitude excitation required for the flame to lift off when forced at higher frequency pressure anti-node conditions. As an extension to the single jet, the shear coaxial jet configuration kept the center fuel and surrounding oxidizer co-flow constant. Only the outer annular oxidizer flowrate was varied, with annulus-to-inner jet velocity ratios ranging from R = 0.05 to 0.3, to investigate its impact on the flame's ability to respond to the acoustics. In the absence of acoustic excitation, the coaxial jet did demonstrate natural shear layer/wake like instabilities at higher annular-to-jet velocity ratios, for R = 0.17 and 0.3. The dynamical response of the coaxial jet to pressure node excitation exhibited similar characteristics to that of the single jet for a range of forcing frequencies. But when forced at a pressure anti-node, a notable difference between the two configurations was found. The shear coaxial jet was more responsive to the acoustic forcing at higher forcing frequencies, for example, than the single fuel jet. The susceptibility diagrams for the full range of annular-to-inner jet velocity ratios demonstrated opposite trends when compared to the single jet, that is, that the coaxial jet was more responsive to excitation at a given excitation amplitude when the forcing frequency was higher, and thus closer to the natural coaxial jet instability frequency. Hence evidence suggests that the natural instabilities of the coaxial jet shear layer may be causing the difference in susceptibility diagrams. Both sets of experimental studies here, the nanofuel droplet combustion studies and the acoustically-coupled turbulent fuel jet combustion experiments, provide useful advances to our understanding of reactive flows relevant to liquid rocket engine systems. Enhancement in burning rates with nanoparticulate additives show potential benefits for rocket fuels, and attendant benefits are documented in the presence of acoustic disturbances, studied separately [1]. AFRL-based acoustically coupled turbulent fuel jet studies reveal different dynamical characteristics, depending on the injection system and the acoustic frequency and amplitude range. Different characteristic signatures extracted via POD analysis are both relevant in understanding combustion instabilities and in developing reduced order models underlying control of such instabilities. The present studies contribute to these goals in important ways.

Download or read book Fossil Energy Update written by and published by . This book was released on 1983 with total page 794 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Heat Transfer Fluid Flow Digest written by and published by . This book was released on 1979 with total page 524 pages. Available in PDF, EPUB and Kindle. Book excerpt: